Improvement in pneumatic pumps



G. WESTBNGHDUSE, Jr.

Pneumatic Pump.

No.l59,533.

Patented Feb. 9,1875.

Alilllllln THE DEZAPHIC CS PHDTO-LTHABS i PARK PLACEJLY.

UNITED STATES PATENT rrron GEORGE WESTINGHOUSE, JR., OF PITTSBURG, PENNSYLVANIA.

lMPROVEMENT IN PNEUMATIC PUMPS.

Specification forming part of Letters Patent No. 159,533, dated February 9, 1875; application filed October 20, 1874.

To all whom it may concern:

Be it known that I, GEORGE Wnsrnvcf- HOUSE, Jr., of Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvement in Pneumatic Pumps; and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawing, making a part of this specification, in which (like letters indicating like parts)- l Figure lis a side elevation of a pumping apparatus illustrative of my improvement, and Fig. 2 is a longitudinal sectional view thereof.

My improvement relates to the construction of a pump for the serial compression of airthat is, for compressing air by a series of pumps, two or more in number, each pump in the series, from the first, compressing the air into the next, till from the last it is compressed into any suitable reservoir, or led off, with or without additional compression, to the place where it is to be used.

In the drawing, c represents a steam-cylinder of the usual or any known construction. It is furnished with a steam-chest, c', the slide-valve of which is operated by the usual tappet-arm c, acting, through kuockers c1, on

v the valve-rod c2; but other suitable known devices may be employed to regulate the supply and exhaust of steam to and from the cylinder a. Arranged in connection with such a steamengine is a series of air-pumps, b, d, and f, in any desired number-two or more. The pistons of these pumps are arranged on a common stem, e; or, if on separate stems, such stems should be so connected, directly or indirectly, with each other and -with the prime motor as that all the pistons should receive a simultaneous motion. Each pump-cylinder has a receiving and a discharging air-port at or near its opposite ends, and from the rst each discharging-port is connected, by a pipe tted with a check-valve, with the corresponding receiving-port of the next pump, and' so on from one -to another throughout the series, till from the discharging-ports of the last pump a pipe or pipes lead olf to the place where the air-is to be stored or used. The receivingports and check-valves of the rst pump are represented at i i, the pipes leading thence to the next pump at o o, and their check-valves by the pressure so given to it and transmitted with it, on the opposite or upper side of the piston of such next pump, and so co-operates or assists in the making of such downstroke, and in like manner, but vice versa, on the upstroke. But, to attain the highest success or material advantage in this operation, I make the successive pump-pistons of a graduallydiminishing area from one to the next, and apportion them all, in relation to each other and to the area of the steam-engine cylinder, (keeping in view the number of pumps employed in the series,) so that, with any given steam-pressure, such as is within the usual limits of ordinary steam-engine machinery, any desired pressure (also within ordinary working limits) may be obtained. The rules governing this apportionment are such as are well known or generally accessible to those skilled in pneumatics; but for purposes of illustration. l will give one set of proportions which, in the apparatus shown, I have found to operate advantageously. The steam-piston 'may be made with an effective area of eight square inches, the first pump-piston with sixteen, the second with eight, and the third with four. Leaving out of view loss-by friction and by expansion of air not ejected at each stroke, the iirst pump, taking in external air at ordinary atmospheric pressure, will, at

each stroke, compress such air into the next of such areas multiplied by the pounds pressure acting on the opposite sides thereof, and dividing the difference by the area of the steam-piston, I get the steam-pressure required to operate the series of pumps shown in doing the Work described, which, in this case, is eighty-five pounds.

With this instruction, those skilled in the art will have no difficulty in calculating the number of pumps required and the relative areas of their pistons as regards each other and the available steam-power, so that, with such steam-power as is ordinarily employed or is conveniently available, any desired airpressure within the limits required for most uses may be secured.

The pumps may be arranged side by side 

